int client_socket = -1; 

int send_message(const char *account, const char *msg) {
    // 拼接协议（示例："ACCOUNT|MSG"）
    char send_buf[MAX_MSG_LEN];
    sprintf(send_buf, "%s|%s", account, msg);

    // 通过 socket 发送
    if (send(client_socket, send_buf, strlen(send_buf), 0) == -1) {
        perror("send() failed");
        return -1; 
    }
    return 0; 
}
